Equilibrium binding of wild-type and mutant Drosophila Heat Shock Factor DNA binding domain with HSE DNA studied by analytical ultracentrifugation

作者：Park Jin Ku^*; Kim Soon Jong

来源：Bulletin of the Korean Chemical Society, 2012, 33(6).

DOI：10.5012/bkcs.2012.33.6.1839

• Analytical ultracentrifuge
• Heat shock factors
• HSF:HSE interaction
• Multiwavelength
• Thermodynamic parameter

We have investigated binding between wild-type and mutant Heat Shock Factor (HSF) DNA binding domains (DBDs) with 17-bp HSE containing a central 5';-NGAAN-3'; element by equilibrium analytical ultracentrifugation using multi-wavelength technique. Our results indicate that R102 plays critical role in HSE recognition and the interactions are characterized by substantial negative changes of enthalpy (ΔH0θ = -9.90 ± 1.13 kcal mol-1) and entropy (ΔS0 θ = -12.46 ± 3.77 cal mol-1K-1) with free energy change, ΔG0θ of -6.15 ± 0.03 kcal mol-1. N105 plays minor role in the HSE interactions with ΔH0θ of -2.54 ± 1.65 kcal mol-1, ΔS0θ of 19.28 ± 5.50 cal mol-1K-1 and ΔG0 θ of -8.35 ± 0.05 kcal mol-1, which are similar to those observed for wild-type DBD:HSE interactions (ΔH 0θ = -3.31 ± 1.86 kcal mol-1, ΔS0θ = 17.38 ± 6.20 cal mol -1K-1 and ΔG0θ= -8.55 ± 0.06 kcal mol-1) indicating higher entropy contribution for both wild-type and N105A DBD bindings to the HSE.

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